This paper deals with the problem of exhaust cross-contamination between vehicles in a slow-moving traffic queue, as would be found in a busy modern city. This study has been undertaken using an open-jet wind tunnel, to determine the level of exhaust contamination around a 1:10 scale model car under various prevailing wind conditions. Tracer-gas techniques have been combined with static pressure measurements, to model the flow of pollutants around a vehicle body.
Plants have been used as initial indicators, or monitors, of air pollutants around industrial sources for a long time (Heck, 1966). Sulfur dioxide (S02) was early identified as causing injury to field-grown plants (Thomas, 1951; Zimmerman & Hitchcock, 1956).
Local age of air and air change effectiveness were determined in two office buildings using tracer gas techniques to study the air applicability of the associated measurement procedures in mechanically ventilated office buildings. Measurement issues examined include the establishment of a uniform tracer gas concentration at the start of the test and the relationship of ventilation system configuration and system operation to the test procedure.
A report on the first part of this investigation of the possibilities of natural ventilation in small utility buildings was presented in 1982. During that investigation it became clear that it was necessary to gather information regarding air-leaks from inside walls and inside doors. This information is required in order to be able to determine the magnitude of the mutual influence of the ventilation in one room on the ventilation in other rooms.
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